The employer, the head of the external company or the self-employed worker shall, where appropriate, set up a radiation protection organisation when the nature and extent of the risk of exposure of workers to ionising radiation leads him to implement at least one of the following measures:
1° The implementation of individual dosimetric monitoring pursuant to I of Article R. 4451-64;
2° Zone demarcation under the conditions set out in Articles R. 4451-22 and R. 4451-28;
3° The checks provided for in section 6 of this chapter.